Neural tube defect is caused by the deficiency of?

BSF Staff Nurse - 2021

Obstetrics and Midwifery Nursing

Easy

Appeared in: BSF Staff Nurse - 2021

Explanation

Folic acid, a B-vitamin, is an essential coenzyme for DNA and RNA synthesis, which is critical for the rapid cell division and growth required for fetal development.
The neural tube, the embryonic precursor to the brain and spinal cord, undergoes closure very early in gestation, typically by the 28th day after conception.
A deficiency of folic acid during this critical window disrupts the closure process, leading to severe congenital anomalies known as neural tube defects (NTDs), such as spina bifida and anencephaly.

Option A: Iron is essential for the synthesis of hemoglobin and the transport of oxygen in the blood. Its deficiency leads to iron-deficiency anemia, not congenital defects of the neural tube.
Option B: Vitamin D is vital for calcium and phosphate metabolism and is essential for bone mineralization. A deficiency causes rickets in children and osteomalacia in adults.
Option D: Immunoglobulins are antibodies produced by the immune system to fight infection. A deficiency, either congenital or acquired, leads to immunodeficiency, not structural birth defects.

Clinical Relevance

Nursing practice connection: This is primarily an exam-oriented knowledge point with limited direct bedside application, so retain Etiology of Neural Tube Defects and Prenatal Nutrition as background academic context rather than a clinical decision trigger.
The cornerstone of NTD prevention is preconception counseling, where nurses play a vital role in educating all women of childbearing age about the importance of daily folic acid supplementation.
Nurses must assess for high-risk factors (e.g., a previous NTD-affected pregnancy, maternal diabetes, obesity, or use of certain antiepileptic drugs like valproate) which necessitate a higher prescribed dose of folic acid (4 mg/day).
What if? If a woman presents for her first antenatal visit in the second trimester without having taken folic acid, the primary window for NTD prevention has passed. The nurse's role shifts to preparing the patient for diagnostic screening (e.g., detailed ultrasound) and providing psychosocial support, while still encouraging folate intake for ongoing fetal growth and maternal health.

How to Approach the Question

Identify the question as a factual recall question linking a nutritional deficiency to a specific clinical condition.
Analyze the core terms: 'Neural tube defect' (a specific congenital anomaly of the brain and spine) and 'deficiency' (lack of a nutrient).
Systematically evaluate each option's primary biological function.
Recall the well-established and heavily emphasized link between folic acid and the prevention of neural tube defects. This is a fundamental concept in maternal and child health nursing.
Rule out the other options by confirming their distinct roles: Iron is for blood production (preventing anemia), Vitamin D is for bone health (preventing rickets), and Immunoglobulins are for immunity (fighting infection).
This process of elimination confirms that folic acid is the only plausible cause among the choices.

Concept Tested & Keywords

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E6 Nelson Textbook of Pediatrics(2024) — Volume 2 p. 1367-1369

E6 Ghai Essential Pediatrics(pp 26-904 of 913) p. 111-113

E6 Parks TextBook of Preventive & Social Medicine part 2 — Subpart A (pp 1-232 of 464) p. 155-157